CN108123639B - Pulse width modulation method, pulse width modulation system and controller - Google Patents

Pulse width modulation method, pulse width modulation system and controller Download PDF

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CN108123639B
CN108123639B CN201611080630.XA CN201611080630A CN108123639B CN 108123639 B CN108123639 B CN 108123639B CN 201611080630 A CN201611080630 A CN 201611080630A CN 108123639 B CN108123639 B CN 108123639B
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modulation
modulation wave
phase
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common
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CN108123639A (en
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刘方诚
辛凯
郭海滨
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Huawei Digital Power Technologies Co Ltd
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Huawei Technologies Co Ltd
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Priority to EP17875630.0A priority patent/EP3537589B1/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/539—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency
    • H02M7/5395—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency by pulse-width modulation
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/501—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode sinusoidal output voltages being obtained by the combination of several pulse-voltages having different amplitude and width
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
    • H02M7/53873—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current with digital control
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
    • H02M7/53875—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current with analogue control of three-phase output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
    • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
    • H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
    • H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
    • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
    • H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
    • H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation
    • H02P27/085—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
    • H02P29/50—Reduction of harmonics
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • H02M1/123—Suppression of common mode voltage or current

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The application provides a pulse width modulation method, a pulse width modulation system and a controller, which are used for changing the change rate of the common-mode component of a three-phase converter along with the change of the modulation degree of the converter, improving the stability and the harmonic characteristic of the three-phase converter and realizing flexible self-adaptive adjustment. The method provided by the embodiment of the invention comprises the following steps: acquiring three-phase initial modulation waves and a modulation degree of a converter; calculating to obtain a common-mode component change rate adjusting coefficient according to preset modulation parameters and a converter modulation degree; calculating to obtain a modulation wave set corresponding to the three-phase initial modulation wave according to a preset modulation wave maximum amplitude, a modulation wave minimum amplitude, the three-phase initial modulation wave and a common-mode component change rate adjustment coefficient, and selecting the modulation wave with the minimum absolute value from the modulation wave set as a common-mode modulation wave; and carrying out waveform superposition on the three-phase initial modulation wave and the common-mode modulation wave to obtain a three-phase output modulation wave.

Description

Pulse width modulation method, pulse width modulation system and controller
Technical Field
The present disclosure relates to the field of circuit technologies, and in particular, to a pulse width modulation method, a pulse width modulation system, and a controller.
Background
With the development of economic society, the energy crisis is gradually highlighted and the global environment is gradually worsened, and the development and use of clean alternative energy has become an important target of the energy industry. With the continuous development of new energy power generation, energy storage and new energy automobile industry, the converter as a core energy control device becomes one of the key factors for clean energy application. Among the many kinds of converters, the three-phase converter is one of the most widely used converters for connecting a three-phase ac power system and a dc power system and realizing energy transfer between the two systems. The two working conditions of rectification and inversion are distinguished according to the difference of the energy flow direction, wherein the energy is transferred from a direct current system to an alternating current system to be called inversion, and the energy is transferred from the alternating current system to the direct current system to be called rectification. Conversion efficiency and power quality are two key technical indexes of a three-phase converter, and the modulation mode directly influences the on-off state of a switching device, so that the conversion efficiency and the power quality are influenced by one of key factors.
A commonly used Pulse Width Modulation (PWM) means of the three-phase converter is Pulse Width Modulation (PWM), that is, the Pulse Width of the driving Pulse of each device in the switching network is controlled. The most direct implementation is to compare the carrier wave with the modulation wave and control the on-off state of the switching device according to the comparison result. PWM can be divided into Continuous Pulse Width Modulation (CPWM) and Discontinuous Pulse Width Modulation (DPWM), and compared with CPWM, DPWM has fewer switching times and thus smaller switching loss, which brings the advantage of being able to improve the energy conversion efficiency of the converter. However, when the adopted modulation mode is DPWM, the harmonic distortion rate is generally higher than that of CPWM, the injected harmonic content is high, and the system resonance is more easily caused, and the lower the modulation degree of the three-phase converter is, the higher the harmonic content injected by DPWM is, while the higher the modulation degree of the three-phase converter is, the injection levels of DPWM and CPWM are close. Therefore, the DPWM is required to be adopted when the modulation degree of the three-phase converter is low and the energy conversion efficiency is considered, and at the moment, the improvement of the common-mode injection method of the DPWM is carried out to reduce the injection common-mode content of the DPWM, so that the reduction of the harmonic content generated by common-mode injection becomes the key point of research.
In order to reduce the harmonic content generated by common mode injection when a three-phase converter adopts DPWM, the two existing technologies are respectively as follows: limiting the rising rate of the common-mode voltage to reduce harmonic waves generated by rapid change of the common-mode voltage, equivalently prolonging the time of the change of the common-mode voltage and reducing the time of the switching state of the three-phase converter; and secondly, taking the direct-current bus voltage as a reference object, measuring the direct-current bus voltage to calculate the clamping time of the switching tube and a corresponding conduction angle, adding a limiting degree link, calculating the common-mode modulation voltage corresponding to three phases according to the direct-current bus voltage, the clamping time of the switching tube and phase information, and calculating the corresponding final modulation voltage according to the fundamental frequency sinusoidal modulation voltage and the common-mode modulation voltage of the three phases.
However, in the first method, if the amplitude limiting value is too small, the time for switching the three-phase converter in the DPWM state cannot be significantly reduced, the advantage of efficiency improvement is reduced, and if the amplitude limiting value is too large, the high-frequency harmonic is difficult to suppress, and the implementation is not flexible; according to actual tests, the common-mode modulation voltage is not determined to be the direct-current bus voltage in the three-phase converter, so that the second method is not suitable for a scene that the three-phase converter adopts the DPWM, the calculation process is complex, the calculation time is too long, and the second method is not suitable for a situation that the three-phase converter is high in switching frequency.
Disclosure of Invention
The application provides a pulse width modulation method, a pulse width modulation system and a controller, which are used for changing the change rate of the common-mode component of a three-phase converter along with the change of the modulation degree of the converter, improving the stability and the harmonic characteristic of the three-phase converter and realizing flexible self-adaptive adjustment.
The invention provides a pulse width modulation method, which is applied to a three-phase current transformer and comprises the following steps:
acquiring three-phase initial modulation waves and a modulation degree of a converter;
calculating to obtain a common-mode component change rate adjusting coefficient according to preset modulation parameters and the modulation degree of the converter, wherein the preset modulation parameters comprise a preset maximum modulation degree, a preset minimum rate of common-mode quantity change between positive and negative clamping states, a preset difference value between the maximum rate and the minimum rate of common-mode quantity change between the positive and negative clamping states and a modulation curvature parameter of the three-phase converter;
calculating to obtain a modulation wave set corresponding to the three-phase initial modulation wave according to a preset maximum amplitude limit value of the modulation wave, a preset minimum amplitude limit value of the modulation wave, the three-phase initial modulation wave and the common-mode component change rate adjustment coefficient, and selecting the modulation wave with the minimum absolute value from the modulation wave set as a common-mode modulation wave;
and performing waveform superposition on the three-phase initial modulation wave and the common-mode modulation wave to obtain a three-phase output modulation wave.
Energy transfer between a three-phase alternating current power system and a direct current power system is generally realized through a three-phase converter, when the modulation mode of the three-phase converter is DPWM, when the modulation degree of the converter is higher, the injected common-mode component of the DPWM is smaller, the output waveform is close to a sine wave at the moment, the requirements of reducing loss and reducing distortion of output current can be met, the change rate of the injected common-mode component is limited less at the moment, when the modulation degree of the converter is reduced gradually, the injected common-mode component of the DPWM is larger gradually, the distortion of the output waveform is serious at the moment, the change rate of the injected common-mode component is reduced, the change rate of the common-mode component is determined by a common-mode component change rate adjusting coefficient, the common-mode component change rate adjusting coefficient is calculated by preset modulation parameters and the modulation degree of the converter, the preset modulation parameters comprise the preset, Presetting minimum modulation degree, presetting minimum rate of common mode quantity change between positive and negative clamping states, presetting difference value between maximum rate and minimum rate of common mode quantity change between positive and negative clamping states and modulation curvature parameters, calculating to obtain modulation wave set corresponding to three-phase initial modulation wave according to preset maximum amplitude limit value of modulation wave, minimum amplitude limit value of modulation wave, three-phase initial modulation wave and common mode component change rate regulation coefficient, selecting modulation wave with minimum absolute value from modulation wave set as common mode modulation wave, finally waveform superposing three-phase initial modulation wave and common mode modulation wave to obtain three-phase output modulation wave, compared with the first method in the prior art, because the change rate of common mode component is determined by modulation degree of converter, and changes along with the change of modulation degree of converter, there is no amplitude limiting link, thus avoiding influence caused by improper amplitude limiting value, compared with the prior art, the stability and harmonic characteristic of the three-phase converter are improved, the change rate of the common-mode component is determined by the modulation degree of the converter, and self-adaptive adjustment is realized.
With reference to the first aspect of the present invention, in the first embodiment of the first aspect of the present invention, the calculating a common mode component change rate adjustment coefficient according to a preset modulation coefficient and the converter modulation degree includes:
obtaining the preset maximum modulation degree M of the three-phase convertermaxPresetting minimum modulation MminPresetting minimum speed K of common mode quantity change between positive and negative clamping statesbPresetting the difference K between the maximum rate and the minimum rate of the common mode quantity change between the positive clamping state and the negative clamping stateaAnd modulating the curvature parameter N, N is greater than 0;
the M is addedmax、Mmin、Kb、KaN and the modulation factor M of the converter into the formula
Figure GDA0001345894000000031
And calculating to obtain a common-mode component change rate adjusting coefficient K.
Before the implementation of the scheme, a preset modulation coefficient is needed, wherein the maximum modulation degree MmaxAnd minimum modulation degree MminIs the maximum modulation factor (generally M) allowed by the three-phase convertermaxNot more than 1.15) and minimum modulation (typically M)minLess than 1) is determined by the design and application scenario of the converter product, therefore, the maximum modulation degree MmaxAnd minimum modulation degree MminEquivalent to two fixed values; minimum rate of common mode change K between positive and negative clamp statesbThe method is determined by the scene where the three-phase converter is located, and can also be freely set by a user; maximum rate of common mode change and K between positive and negative clamp statesbDifference value K ofaIf the maximum rate of common mode variation between positive and negative clamping states allowed by the three-phase converter is 1, then KaIs equal to 1-Kb(ii) a The value of the modulation curvature parameter N is preset, under the condition that N is 1, the common-mode component change rate adjusting coefficient and the converter modulation degree are in a linear relation, and under the condition that N is larger than zero and is not equal to 1, the common-mode component change rate adjusting coefficient and the converter modulation degree are in a curve relation. Is known at M, Mmax、Mmin、Kb、KaAnd under the condition of the value of N, the value of the common-mode component change rate adjusting coefficient K can be obtained through calculation by a formula, and the value of K is determined by M, so that the aim of flexibly adjusting the common-mode component change rate through the modulation degree M of the converter is fulfilled.
With reference to the first aspect and the second aspect of the present invention, in the second aspect of the present invention, the calculating, based on preset maximum amplitude limit values of the modulation waves, minimum amplitude limit values of the modulation waves, the three-phase initial modulation waves, and the common-mode component change rate adjustment coefficient, to obtain a set of modulation waves corresponding to the three-phase initial modulation waves, and selecting the modulation wave with the smallest absolute value from the set of modulation waves as the common-mode modulation wave includes:
obtaining the maximum limit amplitude v of the preset modulation wavemaxAnd modulation degree minimum amplitude limit value vmin；
According to said vmaxSaid vminThe common-mode component change rate regulating coefficient K and a first-phase initial modulation wave v in the three-phase initial modulation waveaCalculating to obtain the vaCorresponding set of modulated waves { vmax-va，K*(vmax/2+vmin/2-va)，vmin-vaV, said vmax-vaIs the vaModulated wave variable in corresponding positive clamp state, said vmin-vaIs the vaModulation wave variable in corresponding negative-clamped state, said K (v)max/2+vmin/2-va) Is the vaModulation wave variables in corresponding switching states;
according to said vmaxSaid vminThe common-mode component change rate regulating coefficient K and a second-phase initial modulation wave v in the three-phase initial modulation wavebCalculating to obtain the vbCorresponding set of modulated waves { vmax-vb，K*(vmax/2+vmin/2-vb)，vmin-vbV, said vmax-vbIs the vbModulated wave variable in corresponding positive clamp state, said vmin-vbIs the vbModulation wave variable in corresponding negative-clamped state, said K (v)max/2+vmin/2-vb) Is the vbModulation wave variables in corresponding switching states;
according to said vmaxSaid vminThe common-mode component change rate regulating coefficient K and a second-phase initial modulation wave v in the three-phase initial modulation wavecCalculating to obtain the vcCorresponding set of modulated waves { vmax-vc，K*(vmax/2+vmin/2-vc)，vmin-vcV, said vmax-vcIs the vcModulated wave variable in corresponding positive clamp state, said vmin-vcIs the vcModulation wave variable in corresponding negative-clamped state, said K (v)max/2+vmin/2-vc) Is the vcModulation wave variables in corresponding switching states;
according to said vaSaid vbAnd said vcObtaining a set of modulation waves { v ] corresponding to the three-phase initial modulation wavemax-va，vmax-vb，vmax-vc，K*(vmax/2+vmin/2-va)，K*(vmax/2+vmin/2-vb)，K*(vmax/2+vmin/2-vc)，vmin-va，vmin-vb，vmin-vc}；
And taking an absolute value of each modulation wave variable in the common-mode modulation wave set, and selecting the modulation wave variable with the minimum absolute value as the common-mode modulation wave.
Maximum amplitude v of modulated wavemaxAnd modulation degree minimum amplitude limit value vminIs preset, because each switch in the three-phase converter corresponds to one switch, and each switch has three clamping states, then according to vmax、vminA common mode component change rate regulating coefficient K and a first phase initial modulation wave v in the three-phase initial modulation waveaV is calculated to obtainaCorresponding set of modulated waves { vmax-va，K*(vmax/2+vmin/2-va)，vmin-va}，vmax-vaIs v isaModulation wave variable v in corresponding positive clamping statemin-vaIs v isaCorresponding modulation wave variable, K (v) in negative-clamped statemax/2+vmin/2-va) Is v isaThe modulation wave variables under the corresponding switching state are sequentially calculated to obtain a second-phase initial modulation wave vbCorresponding set of modulated waves { vmax-vb，K*(vmax/2+vmin/2-vb)，vmin-vbAnd (6) calculating to obtain a third phase initial modulation wave vbCorresponding set of modulated waves { vmax-vb，K*(vmax/2+vmin/2-vb)，vmin-vbAnd merging the modulation wave sets of the three-phase initial modulation waves into a modulation wave set { v } corresponding to the three-phase initial modulation wavesmax-va，vmax-vb，vmax-vc，K*(vmax/2+vmin/2-va)，K*(vmax/2+vmin/2-vb)，K*(vmax/2+vmin/2-vc)，vmin-va，vmin-vb，vmin-vcAnd taking an absolute value of each modulation wave variable in the common-mode modulation wave set, and selecting the modulation wave variable with the minimum absolute value as the common-mode modulation wave.
With reference to the first aspect, the first embodiment of the first aspect, or the second embodiment of the first aspect, in the third embodiment of the first aspect, the waveform-superimposing the three-phase initial modulated wave and the common-mode modulated wave to obtain a three-phase output modulated wave includes:
and carrying out waveform superposition on each phase of initial modulation wave in the three-phase initial modulation wave and the common mode modulation wave in a one-to-one correspondence manner to obtain a three-phase output modulation wave.
After the common-mode modulation waves are obtained, the three-phase converter needs to obtain three-phase output modulation waves by performing waveform superposition on each phase of initial modulation waves in the common-mode modulation waves and the common-mode modulation waves in a one-to-one correspondence manner.
With reference to the first aspect of the present invention, in a fourth embodiment of the first aspect of the present invention, acquiring an initial modulation waveform and a converter modulation degree includes:
acquiring three-phase power grid voltage, three-phase current and a preset carrier amplitude;
performing phase locking processing on the three-phase power grid voltage to obtain a phase of a rotating coordinate system;
according to the phase of the rotating coordinate system, coordinate transformation is carried out on the three-phase current to obtain a current of the rotating coordinate system;
acquiring a preset current reference value of the three-phase current coordinate transformation, and calculating a difference value between the preset current reference value and the current of the rotating coordinate system to obtain a current difference value;
processing the current difference value through a PI regulator to obtain a rotary coordinate system regulation component;
carrying out inverse coordinate transformation on the adjustment component of the rotating coordinate system to obtain a three-phase initial modulation wave;
and obtaining the modulation wave amplitude of the three-phase initial modulation wave, and obtaining the modulation degree of the converter according to the ratio of the modulation wave amplitude to the preset carrier amplitude.
Detecting a three-phase converter to obtain three-phase power grid voltage, three-phase current and a preset carrier amplitude, transmitting the three-phase power grid voltage into a phase-locked loop to obtain a phase of a rotating coordinate system, performing coordinate transformation on the three-phase current according to the phase of the rotating coordinate system to obtain current of the rotating coordinate system, obtaining a preset current reference value of the three-phase current coordinate transformation, calculating a difference value between the preset current reference value and the current of the rotating coordinate system to obtain a current difference value, processing the current difference value through a PI (proportional integral) regulator to obtain a regulated component of the rotating coordinate system, performing inverse coordinate transformation on the regulated component of the rotating coordinate system to obtain a three-phase initial modulated wave, obtaining a modulated wave amplitude of the three-phase initial modulated wave, and obtaining a modulation degree of the converter according to a ratio of the modulated wave amplitude.
The second aspect of the present invention provides a pulse width modulation system applied to a three-phase current transformer, including:
the acquisition module is used for acquiring three-phase initial modulation waves and the modulation degree of the converter;
the calculation module is used for calculating a common-mode component change rate adjustment coefficient according to preset modulation parameters and the modulation degree of the converter, wherein the preset modulation parameters comprise a preset maximum modulation degree, a preset minimum common-mode quantity change rate between positive and negative clamping states, a difference value between the preset maximum common-mode quantity change rate and the preset minimum common-mode quantity change rate between the positive and negative clamping states and modulation curvature parameters of the three-phase converter;
the calculation module is further used for calculating a modulation wave set corresponding to the three-phase initial modulation wave according to a preset maximum amplitude limit value of the modulation wave, a preset minimum amplitude limit value of the modulation wave, the three-phase initial modulation wave and the common-mode component change rate adjustment coefficient, and selecting the modulation wave with the minimum absolute value from the modulation wave set as the common-mode modulation wave;
and the modulation module is also used for performing waveform superposition on the three-phase initial modulation wave and the common-mode modulation wave to obtain a three-phase output modulation wave.
Energy transfer between a three-phase alternating current power system and a direct current power system is generally realized through a three-phase converter, when the modulation mode of the three-phase converter is DPWM, when the modulation degree of the converter is higher, the injected common-mode component of the DPWM is smaller, the output waveform is close to a sine wave at the moment, the requirements of reducing loss and reducing distortion of output current can be met, the change rate of the injected common-mode component is limited less at the moment, when the modulation degree of the converter is reduced gradually, the injected common-mode component of the DPWM is larger gradually, the distortion of the output waveform is serious at the moment, the change rate of the injected common-mode component is reduced, the change rate of the common-mode component is determined by a common-mode component change rate adjusting coefficient, the common-mode component change rate adjusting coefficient is calculated by preset modulation parameters and the modulation degree of the converter, the preset modulation parameters comprise the preset, Presetting minimum modulation degree, presetting minimum rate of common mode quantity change between positive and negative clamping states, presetting difference value between maximum rate and minimum rate of common mode quantity change between positive and negative clamping states and modulation curvature parameters, calculating to obtain modulation wave set corresponding to three-phase initial modulation wave according to preset maximum amplitude limit value of modulation wave, minimum amplitude limit value of modulation wave, three-phase initial modulation wave and common mode component change rate regulation coefficient, selecting modulation wave with minimum absolute value from modulation wave set as common mode modulation wave, finally waveform superposing three-phase initial modulation wave and common mode modulation wave to obtain three-phase output modulation wave, compared with the first method in the prior art, because the change rate of common mode component is determined by modulation degree of converter, and changes along with the change of modulation degree of converter, there is no amplitude limiting link, thus avoiding influence caused by improper amplitude limiting value, compared with the prior art, the stability and harmonic characteristic of the three-phase converter are improved, the change rate of the common-mode component is determined by the modulation degree of the converter, and self-adaptive adjustment is realized.
In combination with the second aspect of the present invention, in the first embodiment of the second aspect of the present invention,
the obtaining module is further configured to obtain a preset maximum modulation degree M of the three-phase convertermaxPresetting minimum modulation MminPresetting minimum speed K of common mode quantity change between positive and negative clamping statesbPresetting the difference K between the maximum rate and the minimum rate of the common mode quantity change between the positive clamping state and the negative clamping stateaAnd modulating the curvature parameter N, N is greater than 0;
the computing module is further configured to compare the Mmax、Mmin、Kb、KaN and the modulation factor M of the converter into the formulaAnd calculating to obtain a common-mode component change rate adjusting coefficient K.
Before the implementation of the scheme, a preset modulation coefficient is needed, wherein the maximum modulation degree MmaxAnd minimum modulation degree MminIs the maximum modulation factor (generally M) allowed by the three-phase convertermaxNot more than 1.15) and minimum modulation (typically M)minLess than 1) is determined by the design and application scenario of the converter product, therefore, the maximum modulation degree MmaxAnd minimum modulation degree MminEquivalent to two fixed values; minimum rate of common mode change K between positive and negative clamp statesbThe method is determined by the scene where the three-phase converter is located, and can also be freely set by a user; maximum rate of common mode change and K between positive and negative clamp statesbDifference value K ofaIf the maximum rate of common mode variation between positive and negative clamping states allowed by the three-phase converter is 1, then KaIs equal to 1-Kb(ii) a The value of the modulation curvature parameter N is preset,and under the condition that N is 1, the common mode component change rate regulating coefficient and the converter modulation degree are in a linear relation, and under the condition that N is larger than zero and is not equal to 1, the common mode component change rate regulating coefficient and the converter modulation degree are in a curve relation. Is known at M, Mmax、Mmin、Kb、KaAnd under the condition of the value of N, the value of the common-mode component change rate adjusting coefficient K can be obtained through calculation by a formula, and the value of K is determined by M, so that the aim of flexibly adjusting the common-mode component change rate through the modulation degree M of the converter is fulfilled.
In combination with the first embodiment of the second aspect of the present invention, in the second embodiment of the second aspect of the present invention,
the obtaining module is further configured to obtain a preset maximum amplitude v of the modulation wavemaxAnd modulation degree minimum amplitude limit value vmin；
The computing module is further configured to compute v from the datamaxSaid vminThe common-mode component change rate regulating coefficient K and a first-phase initial modulation wave v in the three-phase initial modulation waveaCalculating to obtain the vaCorresponding set of modulated waves { vmax-va，K*(vmax/2+vmin/2-va)，vmin-vaV, said vmax-vaIs the vaModulated wave variable in corresponding positive clamp state, said vmin-vaIs the vaModulation wave variable in corresponding negative-clamped state, said K (v)max/2+vmin/2-va) Is the vaModulation wave variables in corresponding switching states;
the computing module is further configured to compute v from the datamaxSaid vminThe common-mode component change rate regulating coefficient K and a second-phase initial modulation wave v in the three-phase initial modulation wavebCalculating to obtain the vbCorresponding set of modulated waves { vmax-vb，K*(vmax/2+vmin/2-vb)，vmin-vbV, said vmax-vbIs the vbCorresponding positive clampModulated wave variable in bit state, said vmin-vbIs the vbModulation wave variable in corresponding negative-clamped state, said K (v)max/2+vmin/2-vb) Is the vbModulation wave variables in corresponding switching states;
the computing module is further configured to compute v from the datamaxSaid vminThe common-mode component change rate regulating coefficient K and a second-phase initial modulation wave v in the three-phase initial modulation wavecCalculating to obtain the vcCorresponding set of modulated waves { vmax-vc，K*(vmax/2+vmin/2-vc)，vmin-vcV, said vmax-vcIs the vcModulated wave variable in corresponding positive clamp state, said vmin-vcIs the vcModulation wave variable in corresponding negative-clamped state, said K (v)max/2+vmin/2-vc) Is the vcModulation wave variables in corresponding switching states;
the computing module is further configured to compute v from the dataaSaid vbAnd said vcObtaining a set of modulation waves { v ] corresponding to the three-phase initial modulation wavemax-va，vmax-vb，vmax-vc，K*(vmax/2+vmin/2-va)，K*(vmax/2+vmin/2-vb)，K*(vmax/2+vmin/2-vc)，vmin-va，vmin-vb，vmin-vc}；
The calculation module is further configured to take an absolute value of each modulation wave variable in the common-mode modulation wave set, and select a modulation wave variable with a smallest absolute value as the common-mode modulation wave.
Maximum amplitude v of modulated wavemaxAnd modulation degree minimum amplitude limit value vminIs preset, because each switch in the three-phase converter corresponds to one switch, and each switch has three clamping states, then according to vmax、vminA common mode component change rate regulating coefficient K and a first phase initial modulation wave v in the three-phase initial modulation waveaV is calculated to obtainaCorresponding set of modulated waves { vmax-va，K*(vmax/2+vmin/2-va)，vmin-va}，vmax-vaIs v isaModulation wave variable v in corresponding positive clamping statemin-vaIs v isaCorresponding modulation wave variable, K (v) in negative-clamped statemax/2+vmin/2-va) Is v isaThe modulation wave variables under the corresponding switching state are sequentially calculated to obtain a second-phase initial modulation wave vbCorresponding set of modulated waves { vmax-vb，K*(vmax/2+vmin/2-vb)，vmin-vbAnd (6) calculating to obtain a third phase initial modulation wave vbCorresponding set of modulated waves { vmax-vb，K*(vmax/2+vmin/2-vb)，vmin-vbAnd merging the modulation wave sets of the three-phase initial modulation waves into a modulation wave set { v } corresponding to the three-phase initial modulation wavesmax-va，vmax-vb，vmax-vc，K*(vmax/2+vmin/2-va)，K*(vmax/2+vmin/2-vb)，K*(vmax/2+vmin/2-vc)，vmin-va，vmin-vb，vmin-vcAnd taking an absolute value of each modulation wave variable in the common-mode modulation wave set, and selecting the modulation wave variable with the minimum absolute value as the common-mode modulation wave.
With reference to the second aspect of the present invention, the first embodiment of the second aspect of the present invention, or the second embodiment of the second aspect of the present invention, in a third embodiment of the second aspect of the present invention,
the modulation module is specifically configured to perform waveform superposition on each phase of the initial modulation wave in the three-phase initial modulation wave and the common mode modulation wave in a one-to-one correspondence manner, so as to obtain a three-phase output modulation wave.
After the common-mode modulation waves are obtained, the three-phase converter needs to obtain three-phase output modulation waves by performing waveform superposition on each phase of initial modulation waves in the common-mode modulation waves and the common-mode modulation waves in a one-to-one correspondence manner.
In combination with the second aspect of the present invention, in a fourth embodiment of the second aspect of the present invention,
the acquisition module is used for acquiring three-phase power grid voltage, three-phase current and a preset carrier amplitude;
the calculation module is also used for carrying out phase locking processing on the three-phase power grid voltage to obtain a phase of a rotating coordinate system;
the calculation module is further used for performing coordinate transformation on the three-phase current according to the phase of the rotating coordinate system to obtain a current of the rotating coordinate system;
the acquisition module is further used for acquiring a preset current reference value of the three-phase current coordinate transformation, and calculating a difference value between the preset current reference value and the current of the rotating coordinate system to obtain a current difference value;
the calculation module is also used for processing the current difference value through a proportional integral PI regulator to obtain a rotating coordinate system regulation component;
the calculation module is further configured to perform inverse coordinate transformation on the rotating coordinate system adjustment component to obtain a three-phase initial modulation wave;
the calculation module is further configured to obtain a modulation wave amplitude of the three-phase initial modulation wave, and obtain a modulation degree of the converter according to a ratio of the modulation wave amplitude to the preset carrier amplitude.
The method comprises the steps that an obtaining module detects a three-phase converter to obtain three-phase power grid voltage, three-phase current and a preset carrier amplitude, a calculating module sends the three-phase power grid voltage to a phase-locked loop to obtain a phase of a rotating coordinate system, coordinate transformation is conducted on the three-phase current according to the phase of the rotating coordinate system to obtain current of the rotating coordinate system, a preset current reference value of the three-phase current coordinate transformation is obtained, a difference value between the preset current reference value and the current of the rotating coordinate system is calculated to obtain a current difference value, the current difference value is processed through a PI regulator to obtain a regulating component of the rotating coordinate system, anti-coordinate transformation is conducted on the regulating component of the rotating coordinate system to obtain a three-phase initial modulating wave, a modulating wave amplitude of the three-phase initial modulating wave is obtained, and.
The third aspect of the present invention provides a controller for a three-phase converter, including:
the processor, the memory and the signal interface are connected with each other, the memory is stored with the operation instruction of the processor,
the processor, the memory and the signal interface are connected with each other, the memory is stored with the operation instruction of the processor,
the signal interface is used for acquiring three-phase initial modulation waves and the modulation degree of the converter;
the processor is used for calculating to obtain a common mode component change rate adjusting coefficient according to preset modulation parameters and the modulation degree of the converter, wherein the preset modulation parameters comprise a preset maximum modulation degree, a preset minimum rate of common mode quantity change between positive and negative clamping states, a difference value between the preset maximum rate and the preset minimum rate of common mode quantity change between the positive and negative clamping states and modulation curvature parameters of the three-phase converter;
the processor is further configured to calculate a modulation wave set corresponding to the three-phase initial modulation wave according to a preset maximum amplitude limit of the modulation wave, a preset minimum amplitude limit of the modulation wave, the three-phase initial modulation wave and the common-mode component change rate adjustment coefficient, and select the modulation wave with the smallest absolute value from the modulation wave set as the common-mode modulation wave;
the processor is further configured to perform waveform superposition on the three-phase initial modulation wave and the common-mode modulation wave to obtain a three-phase output modulation wave.
The common mode component change rate regulating coefficient is calculated by a processor according to preset modulating parameters and the modulating degree of the converter, the preset modulating parameters comprise preset maximum modulating degree, preset minimum modulating degree of the three-phase converter, preset minimum common mode change rate between positive and negative clamping states, difference value between the maximum common mode change rate and the minimum common mode change rate between the positive and negative clamping states and modulating curvature parameters, a modulating wave set corresponding to the three-phase initial modulating wave is calculated according to preset modulating wave maximum amplitude limit, modulating wave minimum amplitude limit, three-phase initial modulating wave and the common mode component change rate regulating coefficient, the modulating wave with the minimum absolute value is selected from the modulating wave set as a common mode modulating wave, finally, the three-phase initial modulating wave and the common mode modulating wave are subjected to waveform superposition to obtain a three-phase output modulating wave, compared with the first method in the prior art, because the change rate of the common-mode component is determined by the modulation degree of the converter, the common-mode component changes along with the change of the modulation degree of the converter, and no amplitude limiting link exists, the influence caused by improper amplitude limiting value can be avoided, the stability and the harmonic characteristic of the three-phase converter are improved, compared with the second prior art, the change rate of the common-mode component is determined by the modulation degree of the converter, and the self-adaptive adjustment is realized.
Drawings
In order to more clearly illustrate the technical solution of the embodiment of the present invention, the following briefly introduces the embodiment and the drawings used in the description of the prior art.
Fig. 1 is a system structural diagram of a three-phase converter provided in the present application;
FIG. 2 is a waveform diagram of a common mode signal provided herein;
FIG. 3 is a graph of the modulation degree and harmonic distortion rate of the current transformer according to the present application;
fig. 4 is a waveform diagram of a DPWM modulation wave when a converter modulation degree M is 1.1 according to the present application;
fig. 5 is a waveform diagram of a DPWM modulation wave when a converter modulation degree M is 0.88 according to the present application;
FIG. 6 is a schematic flow chart diagram illustrating one embodiment of a pulse width modulation method provided herein;
fig. 7 is a schematic structural diagram of a three-level grid-connected photovoltaic inverter provided by the present application;
fig. 8 is a schematic diagram of a control algorithm of a three-level grid-connected photovoltaic inverter provided by the present application;
fig. 9 is a relationship diagram of modulation curvature parameters, modulation degrees of a current transformer, and modulation coefficients of a change rate of common mode components provided by the present application;
fig. 10 is a graph comparing the DPWM of the present invention and the conventional DPWM when the modulation factor M of the converter provided by the present application is 1.1;
fig. 11 is a graph comparing the DPWM of the present invention and the conventional DPWM when the modulation degree M of the converter provided by the present application is 0.8;
FIG. 12 is a schematic block diagram of one embodiment of a pulse width modulation system provided herein;
FIG. 13 is a schematic structural diagram of an exemplary controller configuration provided herein;
fig. 14 is a schematic structural diagram of a two-level rectifier and converter provided in the present application;
fig. 15 is a schematic structural diagram of a three-level rectifier and converter provided in the present application;
fig. 16 is a schematic structural diagram of a five-level rectifier and a converter provided in the present application;
fig. 17 is a schematic structural diagram of a cascaded multi-level rectifier and converter provided in the present application.
Detailed Description
The application provides a pulse width modulation method, a pulse width modulation system and a controller, which are used for changing the change rate of the common-mode component of a three-phase converter along with the change of the modulation degree of the converter, improving the stability and the harmonic characteristic of the three-phase converter and realizing flexible self-adaptive adjustment.
The technical solutions in the present application will be described clearly and completely with reference to the accompanying drawings in the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
First, a system architecture or scenario in which the present invention is applied will be briefly described.
The invention is applied to a converter, in particular to a three-phase converter which is most widely applied at present and is used for connecting a three-phase alternating current power system and a direct current power system and realizing energy transfer between the two systems. The two working conditions of rectification and inversion are distinguished according to the difference of the energy flow direction, wherein the energy is transferred from a direct current system to an alternating current system to be called inversion, and the energy is transferred from the alternating current system to the direct current system to be called rectification. Therefore, in most application scenarios, both rectification and inversion can be realized by using the same system, and a system structure of a typical three-phase converter is shown in fig. 1 and includes a direct current system, a switching network, a controller, a filter and an alternating current system, where the filter is used for filtering alternating current during rectification, the switching network includes switching devices, and the controller controls on/off actions of the switching devices in the switching network by a modulation method, so as to turn on and off energy transfer between the alternating current system and the direct current system.
The pulse width modulation method adopted by the three-phase converter is PWM, namely the width of the driving pulse of each device in the switch network is controlled. The most direct implementation is to compare the carrier wave with the modulation wave and control the on-off state of the switching device according to the comparison result. PWM can be further classified into CPWM and DPWM. CPWM means that each phase of bridge arm always has a switching action in each switching period, and a common mode is Sinusoidal Pulse Width Modulation (SPWM); DPWM means that a certain phase arm of a converter is clamped to a positive dc bus or a negative dc bus in a certain switching period, and the phase switching device is normally on or off and does not perform a switching operation in the clamping period. Common DPWM modulations include DPWM0, DPWM1, DPWM2, DPWM3, DPWMMAX, DPWMMIN and GDPWM (general DPWM).
In a specific implementation, the modulation wave of the DPWM can be realized by superimposing an equivalent common-mode component on the modulation wave of the CPWM. For example, comparing a DPWM modulation waveform within a power frequency period (e.g., 50Hz) with an SPWM modulation waveform (a kind of CPWM), as shown in fig. 2, the difference between the DPWM modulation waveform and the power frequency sine wave is the waveform of the common mode signal shown in fig. 2. Since the modulation wave of the DPWM can be equivalent to the sum of the SPWM modulation wave and the common mode signal, the output characteristic of the DPWM is affected by both the SPWM output characteristic and the common mode signal output characteristic. The injected common-mode signal can affect the quality of the converter power and even generate resonance, thereby affecting the system stability. Fig. 3 is a graph showing a relationship between a modulation degree M and a harmonic distortion rate HDF of a converter in a conventional PWM modulation method. As can be seen from fig. 3, the harmonic distortion rate of the DPWM modulation method is generally higher than that of the CPWM modulation method, but when the modulation degree is relatively high, the harmonic distortion rates of the DPWM and the CPWM are relatively close, the common-mode signal component injected in the DPWM modulation is relatively small, and when the modulation degree is relatively low, the common-mode signal amount injected for realizing the clamping is relatively large, and the harmonic distortion rate of the DPWM is much larger than that of the CPWM. Therefore, there is a need for improving the common-mode injection of DPWM at low modulation levels to reduce its injection common-mode content, and thus reduce the harmonic content generated by common-mode injection.
As can be seen from the prior art, when the converter modulation degree is relatively large, the common mode signal for implementing DPWM injection is relatively small, and as shown in fig. 4, a schematic diagram of a DPWM modulation wave is shown when the converter modulation degree M is 1.1. At the moment, the common mode signal for realizing DPWM injection is small, the output waveform is close to a sine wave, the distortion of the output current is small, the conventional DPWM modulation is adopted, and the change rate of the injected common mode component is limited less; when the modulation degree of the converter is small, the common-mode signal for implementing DPWM injection is large, and as shown in fig. 5, the DPWM modulation wave is schematically illustrated when the modulation degree M of the converter is 0.88, at this time, the distortion of the output waveform is serious, and the change rate of the injected common-mode component should be reduced, the high-frequency component of the common-mode component should be reduced, and the impact and the current distortion brought by the drastic change of the common-mode component to the converter are reduced.
In the current DPWM scheme, since the three-phase converter has 3 bridge arms, each bridge arm can generate positive clamping, negative clamping and switching 3 states, and the 3 bridge arms totally 9 states respectively correspond to 9 modulation waves. However, the three-phase converter can only realize one clamping state at any moment, otherwise, the converter is out of control, and therefore, the three-phase converter has three possible clamping states: positive clamp state, negative clamp state, and switching state. According to analysis, the efficiency improvement of the switching on the three-phase converter is far smaller than that of positive clamping and negative clamping, the switching state is a transition state of the positive clamping state and the negative clamping state, and the component of the common-mode voltage in the switching state directly influences the finally superposed common-mode component.
The invention provides a pulse width modulation method for solving the influence of common mode components on a three-phase converter in a switching state, which comprises the following steps:
referring to fig. 6, an embodiment of the invention provides a pulse width modulation method, including:
601. acquiring three-phase initial modulation waves and a modulation degree of a converter;
in this embodiment, the three-phase initial modulation wave is an initial modulation wave of each phase of a three-phase ac machine control loop, the control loop includes one or more combinations of a voltage control loop, a current control loop and a power control loop, the modulation degree of the converter can be obtained by calculating a ratio of an ac voltage peak value and a dc voltage of the converter or by calculating a peak value and a carrier peak value of the three-phase initial modulation wave, and the three-phase converter controls the voltage and the current of the converter by adjusting the modulation wave, so that the modulation wave is dynamically changed. When the converter enters a stable operation state, the modulation wave is periodically repeated, and the peak value of the modulation wave can be regarded as a fixed value, so that the modulation degree of the converter can be accurately obtained.
602. Calculating to obtain a common-mode component change rate adjusting coefficient according to preset modulation parameters and a converter modulation degree;
in this embodiment, the preset modulation parameters include a preset maximum modulation degree, a preset minimum rate of common mode change between positive and negative clamping states, a difference between the preset maximum rate of common mode change and the preset minimum rate between the positive and negative clamping states, and a modulation curvature parameter, where the preset maximum modulation degree and the preset minimum modulation degree are determined by the product design and application scenarios of the three-phase converter, the preset minimum rate of common mode change between the positive and negative clamping states, and the difference between the preset maximum rate of common mode change and the preset minimum rate between the positive and negative clamping states are determined by the scenario in which the three-phase converter is located, or can be freely set by a user, and the modulation curvature parameter is also preset, so that the values of each parameter in the preset modulation parameters are known before the implementation of the scheme, and the common mode component change rate adjustment coefficient is calculated according to the preset modulation parameter and the modulation degree of the converter, the common-mode component change rate adjusting coefficient is used for the change rate of the common-mode component, and the larger the value is, the faster the change rate of the common-mode component is.
603. Calculating to obtain a modulation wave set corresponding to the three-phase initial modulation wave according to a preset modulation wave maximum amplitude, a modulation wave minimum amplitude, the three-phase initial modulation wave and a common-mode component change rate adjustment coefficient, and selecting the modulation wave with the minimum absolute value from the modulation wave set as a common-mode modulation wave;
in this embodiment, the maximum amplitude limit and the minimum amplitude limit of the modulation wave are preset, and since each switch in the three-phase converter corresponds to one switch, each switch has three clamp states, a modulation wave in three clamp states can be obtained for each phase of modulation wave in the three-phase initial modulation wave, so that a modulation wave set corresponding to the three-phase initial modulation wave obtained by calculation includes nine modulation waves, and the modulation wave with the minimum absolute value is selected from the nine modulation waves in the modulation wave set as the common mode modulation wave.
604. And carrying out waveform superposition on the three-phase initial modulation wave and the common-mode modulation wave to obtain a three-phase output modulation wave.
In this embodiment, the three-phase initial modulation wave and the common mode modulation wave are waveform-superposed to obtain a corresponding three-phase output modulation wave, and as can be observed from the waveform distortion of the three-phase output modulation wave, the modulation degree of the converter is proportional to the change rate of the common mode component.
In the embodiment of the invention, the changing speed of the common-mode component is determined by a common-mode component changing rate regulating coefficient, the common-mode component changing rate regulating coefficient is calculated by a preset modulating parameter and a converter modulating degree, the preset modulating parameter comprises a preset maximum modulating degree, a preset minimum modulating degree, a preset common-mode changing minimum rate between a positive clamping state and a negative clamping state of the three-phase converter, a difference value between the preset common-mode changing maximum rate and the preset minimum rate between the positive clamping state and the negative clamping state and a modulating curvature parameter, a modulating wave set corresponding to the three-phase initial modulating wave is calculated according to a preset modulating wave maximum amplitude limit value, a modulating wave minimum amplitude limit value, a three-phase initial modulating wave and the common-mode component changing rate regulating coefficient, the modulating wave with the minimum absolute value is selected from the modulating wave set as a common-mode modulating wave, and finally the three-phase initial modulating wave and the common-mode modulating wave are superposed, compared with the method I in the prior art, the change rate of the common-mode component is determined by the modulation degree of the converter, changes along with the change of the modulation degree of the converter, and has no amplitude limiting link, so that the influence caused by improper amplitude limiting value can be avoided, the stability and harmonic characteristic of the three-phase converter are improved, and compared with the method II in the prior art, the change rate of the common-mode component is determined by the modulation degree of the converter, and self-adaptive adjustment is realized.
The three-phase converter can be divided into an inverter state and a rectifier state, and the scheme of the invention can be applied to the inverter or the rectifier, taking the photovoltaic inverter application system shown in fig. 7 as an example, the inverter structure is a two-level structure, the direct-current bus is connected with the photovoltaic cell panel, and the alternating-current port is connected with a three-phase alternating-current power grid through an L filter. The positive direction of the current is defined as the direction of the current flowing out of the bridge arm port of the inverter in the control system, and an algorithm chart of the inverter is shown in fig. 8.
Optionally, in some embodiments of the present invention, obtaining a three-phase initial modulation wave and a modulation degree of the converter includes:
acquiring three-phase power grid voltage, three-phase current and a preset carrier amplitude;
performing phase locking processing on the three-phase power grid voltage to obtain a phase of a rotating coordinate system;
according to the phase of the rotating coordinate system, coordinate transformation is carried out on the three-phase current to obtain a current of the rotating coordinate system;
acquiring a preset current reference value of three-phase current coordinate transformation, and calculating a difference value between the preset current reference value and the current of the rotating coordinate system to obtain a current difference value;
processing the current difference value through a PI regulator to obtain a rotary coordinate system regulation component;
carrying out inverse coordinate transformation on the adjustment component of the rotating coordinate system to obtain a three-phase initial modulation wave;
and obtaining the modulation wave amplitude of the three-phase initial modulation wave, and obtaining the modulation degree of the converter according to the ratio of the modulation wave amplitude to the preset carrier amplitude.
In the embodiment of the invention, the photovoltaic inverter shown in fig. 8 is combined to obtain the three-phase power grid voltage vga、vgbAnd vgcAnd three-phase current ia、ibAnd icAnd the modulation degree M of the converter, firstly the three-phase network voltage vga、vgbAnd vgcSending into Phase Locked Loop (PLL) to obtain phase theta of rotating coordinate system, and applying three-phase current ia、ibAnd icPerforming coordinate transformation to obtain the current i in the rotating coordinate systemdAnd iqThe coordinate Transformation is calculated by Park Transformation (Park Transformation), and the calculation equation is as follows:
Figure GDA0001345894000000171
will calculate the obtained idAnd iqWith its reference value idrefAnd iqrefComparing, and respectively sending the difference values to a regulator GdAnd GqObtaining the adjusting component v of the d-axis and q-axis rotating coordinate systemdAnd vqWherein G isdAnd GqAre proportional-integral (PI) regulators.
For the regulation component vdAnd vqCarrying out inverse coordinate transformation to obtain the equivalent value v of the coordinate system in a static coordinate systema、vbAnd vcThe calculation method is Inverse Park Transformation (Inverse Park Transformation), and the calculation equation is as follows:
Figure GDA0001345894000000172
according to three-phase initial modulation wave va、vbAnd vcAnd obtaining the modulation degree of the inverter, namely the modulation degree of the converter, by the amplitude value of the modulation wave and the ratio of the amplitude value of the preset carrier wave.
It should be noted that, in the above embodiment, the three-phase initial modulation wave is obtained according to the coordinate transformation of the three-phase grid voltage and the three-phase current, which is only one way to obtain the initial modulation wave, and in practical application, there may be other ways, which are not limited specifically.
Optionally, in some embodiments of the present invention, the calculating to obtain the common-mode component change rate adjustment coefficient according to a preset modulation coefficient and a modulation degree of the converter includes:
obtaining the preset maximum modulation M of the three-phase convertermaxPresetting minimum modulation MminPresetting minimum speed K of common mode quantity change between positive and negative clamping statesbPresetting the difference K between the maximum rate and the minimum rate of the common mode quantity change between the positive clamping state and the negative clamping stateaAnd modulating the curvature parameter N, N is greater than 0;
will Mmax、Mmin、Kb、KaN and the converter modulation M are substituted into the following formula:
Figure GDA0001345894000000173
and calculating to obtain a common-mode component change rate adjusting coefficient K.
In the embodiment of the invention, according to the modulation degree M of the converter and a preset modulation coefficient, a formula for calculating the common-mode component change rate adjustment coefficient K is as follows:
Figure GDA0001345894000000174
wherein the maximum modulation degree MmaxAnd minimum modulation degree MminIs the maximum modulation factor (generally M) allowed by the three-phase convertermaxNot more than 1.15) and minimum modulation (typically M)minLess than 1) is determined by the design and application scenario of the converter product, therefore, the maximum modulation degree MmaxAnd minimum modulation degree MminEquivalent to two fixed values; minimum rate of common mode change K between positive and negative clamp statesbThe method is determined by the scene where the three-phase converter is located, and can also be freely set by a user; maximum rate of common mode change and K between positive and negative clamp statesbDifference value K ofaIf the maximum rate of common mode variation between positive and negative clamping states allowed by the three-phase converter is 1, then KaIs equal to 1-Kb(ii) a The value of the modulation curvature parameter N is preset, the preset common-mode component adjusting formula is a linear formula when N is 1, and the preset common-mode component adjusting formula is a curve equation when N is larger than zero and is not equal to 1. Get M, M in the get modulemax、Mmin、Kb、KaAnd under the condition of the value of N, the calculation module can calculate the value of the common-mode component change rate adjusting coefficient K through a formula, and Mmax、Mmin、Kb、KaAnd the value of N is preset and adjustable, the value of K is determined by M, and the aim of flexibly adjusting the change rate of the common-mode component through the modulation degree M of the converter is fulfilled.
Suppose MmaxIs 1.15, MminIs 0.8, N is 1, KaAnd KbIf the common-mode component variation rate is 0.5, the common-mode component variation rate adjusting coefficient K can be calculated according to M, and the mathematical relationship is as follows:
Figure GDA0001345894000000181
for example, in fig. 9, when N is 0.01, it can be seen that the K value in most ranges is close to or equal to 1, so that the range of the switching state is relatively large, and when the K value is not equal to 1, the coverage range of the transition state is relatively small. This requirement is commonly set in conjunction with the three-phase converter hardware system architecture and parameters. Similarly, if N is 99, it can be seen that the transient state (K is not equal to 1) occupies most of the space, and the switching state (K is 1) is only realized at the time of the maximum modulation degree, so the preset modulation factor can reduce the time for switching the states of the three-phase converter, and further improve the efficiency of the three-phase converter.
Optionally, in some embodiments of the present invention, a modulated wave set corresponding to the three-phase initial modulated wave is obtained by calculation according to a preset maximum amplitude of the modulated wave, a preset minimum amplitude of the modulated wave, the three-phase initial modulated wave, and a common-mode component change rate adjustment coefficient, and the modulated wave with the minimum absolute value is selected from the modulated wave set as the common-mode modulated wave, where the method includes:
obtaining the maximum limit amplitude v of the preset modulation wavemaxAnd modulation degree minimum amplitude limit value vmin；
According to said vmaxSaid vminThe common-mode component change rate regulating coefficient K and a first-phase initial modulation wave v in the three-phase initial modulation waveaCalculating to obtain the vaCorresponding set of modulated waves { vmax-va，K*(vmax/2+vmin/2-va)，vmin-vaV, said vmax-vaIs the vaModulated wave variable in corresponding positive clamp state, said vmin-vaIs the vaModulation wave variable in corresponding negative-clamped state, said K (v)max/2+vmin/2-va) Is the vaModulation wave variables in corresponding switching states;
according to said vmaxSaid vminThe common-mode component change rate regulating coefficient K and a second-phase initial modulation wave v in the three-phase initial modulation wavebCalculating to obtain the vbCorresponding set of modulated waves { vmax-vb，K*(vmax/2+vmin/2-vb)，vmin-vbV, said vmax-vbIs the vbModulated wave variable in corresponding positive clamp state, said vmin-vbIs the vbModulation wave variable in corresponding negative-clamped state, said K (v)max/2+vmin/2-vb) Is the vbModulation wave variables in corresponding switching states;
according to said vmaxSaid vminThe common-mode component change rate regulating coefficient K and the second-phase initial modulation in the three-phase initial modulation waveWave vcCalculating to obtain the vcCorresponding set of modulated waves { vmax-vc，K*(vmax/2+vmin/2-vc)，vmin-vcV, said vmax-vcIs the vcModulated wave variable in corresponding positive clamp state, said vmin-vcIs the vcModulation wave variable in corresponding negative-clamped state, said K (v)max/2+vmin/2-vc) Is the vcModulation wave variables in corresponding switching states;
according to said vaSaid vbAnd said vcObtaining a set of modulation waves { v ] corresponding to the three-phase initial modulation wavemax-va，vmax-vb，vmax-vc，K*(vmax/2+vmin/2-va)，K*(vmax/2+vmin/2-vb)，K*(vmax/2+vmin/2-vc)，vmin-va，vmin-vb，vmin-vc}；
And taking an absolute value of each modulation wave variable in the common-mode modulation wave set, and selecting the modulation wave variable with the minimum absolute value as the common-mode modulation wave.
In the embodiment of the invention, the maximum amplitude value and the minimum amplitude value of a modulation wave need to be preset, a preset modulation wave amplitude limit value is obtained, three-phase initial modulation waves, a common-mode component change rate regulation coefficient and a modulation wave amplitude limit value are substituted into a preset common-mode modulation wave variable set, and each switch has three clamping states because each switch corresponds to one switch in a three-phase converter, so that the preset common-mode modulation wave variable set comprises modulation wave variables of a positive clamping state, a negative clamping state and a switching state corresponding to each phase initial modulation wave, the number of the modulation wave variables is nine, and the modulation wave variable with the smallest absolute value is selected as the common-mode modulation wave for influencing the stability of a system. Suppose the modulation amplitude is vmax＝1，v min1, three-phase initial modulation wave va、vbAnd vcCommon mode component change rate adjustment coefficient K and modulation amplitude limit value vmax＝1，vminSubstituting preset common mode modulation wave variable set {1-v ═ 1a，1-vb，1-vc，K*(1/2+-1/2-va)，K*(1/2+-1/2-vb)，K*(1/2+-1/2-vc)，-1-va，-1-vb，-1-vcAnd the frequency converter comprises nine variables, and the variable with the smallest absolute value in the nine variables is selected as the common-mode modulation wave vZThe calculation process is as follows:
1. when 1-max { v }a,vb,vcThe absolute value of which is less than-1-min { v }a,vb,vcAbsolute value of, K x min { v }a,vb,vcThe absolute value of and K max { v }a,vb,vcAbsolute value of vZ＝1-max{va,vb,vc}；
2. When K is min { v }a,vb,vcThe absolute value of which is less than 1-max va,vb,vcAbsolute value of-1-min { v }a,vb,vcThe absolute value of and K max { v }a,vb,vcAbsolute value of vZ＝-K*min{va,vb,vc}；
3. When K max { v }a,vb,vcThe absolute value of which is less than 1-max va,vb,vcAbsolute value of-1-min { v }a,vb,vcThe absolute value of and K x min { v }a,vb,vcAbsolute value of vZ＝-K*max{va,vb,vc}；
4. When-1-min { v }a,vb,vcThe absolute value of which is less than 1-max va,vb,vcAbsolute value of, K x min { v }a,vb,vcThe absolute value of and K max { v }a,vb,vcAbsolute value of vZ＝-1-min{va,vb,vc}。
Optionally, in some embodiments of the present invention, waveform superposition is performed on the three-phase initial modulation wave and the common-mode modulation wave to obtain a three-phase output modulation wave, where the waveform superposition includes:
and carrying out waveform superposition on each phase of initial modulation wave in the three-phase initial modulation wave and the common-mode modulation wave in a one-to-one correspondence manner to obtain a three-phase output modulation wave.
In the embodiment of the invention, the common mode modulation wave vZAnd three-phase initial modulation wave va、vbAnd vcRespectively added to obtain new three-phase output modulated wave va_mod、vb_modAnd vc_mod。
Comparing the implementation effect of the technical solution of the present invention with the effect of the conventional DPWM scheme, where the comparison result when the converter modulation degree M is 1.1 is shown in fig. 10, fig. 10(a) and 10(b) are conventional DPWM modulation waveform and injected common mode spectrum diagram when the converter modulation degree M is 1.1, and fig. 10(c) and 10(d) are DPWM modulation waveform and injected common mode spectrum diagram of the present invention. As can be seen from comparison of fig. 10, when the modulation degree M is high, the waveform and the frequency spectrum characteristics of the modulation are very close to those of the conventional DPWM method. At the moment, the high-frequency component of the injected common-mode signal is small, the limitation on a common-mode voltage source is not needed, the switch clamping effect of the converter can be maximized, and the efficiency is improved.
Fig. 11 shows the comparison result when the converter modulation degree M is 0.8, fig. 11(a) and fig. 11(b) are the conventional DPWM modulation waveform and the injected common mode spectrum diagram when the converter modulation degree M is 0.8, fig. 11(c) and fig. 11(d) are the DPWM modulation waveform and the injected common mode spectrum diagram of the present invention, and it can be seen from the comparison of fig. 11 that the common mode component injected by the conventional DPWM increases as the modulation degree decreases. When the modulation degree is low, the difference between the modulation waveforms of the scheme and the conventional DPWM method is large, the injected common-mode component of the scheme is smooth, and the frequency spectrum component is far smaller than that of the conventional DPWM scheme.
The above embodiments describe the pulse width modulation method, and the pulse width modulation system is explained by the embodiments below.
Referring to fig. 12, the present invention provides a pulse width modulation system applied to a three-phase current transformer, including:
an obtaining module 1201, configured to obtain a three-phase initial modulation wave and a modulation degree of a converter;
the calculating module 1202 is configured to calculate a common mode component change rate adjustment coefficient according to preset modulation parameters and a modulation degree of the converter, where the preset modulation parameters include a preset maximum modulation degree, a preset minimum rate of common mode quantity change between positive and negative clamp states, a difference between the preset maximum rate and the preset minimum rate of common mode quantity change between the positive and negative clamp states, and a modulation curvature parameter;
the calculating module 1202 is further configured to calculate a modulation wave set corresponding to the three-phase initial modulation wave according to a preset modulation wave maximum amplitude, a preset modulation wave minimum amplitude, a preset three-phase initial modulation wave and a preset common-mode component change rate adjustment coefficient, and select a modulation wave with a minimum absolute value from the modulation wave set as a common-mode modulation wave;
the modulation module 1203 is further configured to perform waveform superposition on the three-phase initial modulation wave and the common-mode modulation wave to obtain a three-phase output modulation wave.
In the embodiment of the present invention, the changing speed of the common mode component is determined by a common mode component changing rate adjusting coefficient, the common mode component changing rate adjusting coefficient is calculated by the calculating module 1202 according to the modulation degree of the converter obtained by the obtaining module 1201, the calculating module 1202 obtains a common mode modulation wave according to the three-phase initial modulation wave and the common mode component changing rate adjusting coefficient, and the modulating module 1203 obtains a three-phase output modulation wave according to the three-phase initial modulation wave and the common mode modulation wave, compared with the first prior art, because the changing rate of the common mode component is determined by the modulation degree of the converter, changes along with the change of the modulation degree of the converter, and has no clipping link, the influence caused by improper clipping value can be avoided, the stability and the harmonic characteristic of the three-phase converter are improved, compared with the second prior art, the changing rate of the common mode component is determined, adaptive adjustment is achieved.
Alternatively, in some embodiments of the present invention,
an obtaining module 1201, further configured to obtain a pre-phase of the three-phase converterSetting maximum modulation degree MmaxPresetting minimum modulation MminPresetting minimum speed K of common mode quantity change between positive and negative clamping statesbPresetting the difference K between the maximum rate and the minimum rate of the common mode quantity change between the positive clamping state and the negative clamping stateaAnd modulating the curvature parameter N, N is greater than 0;
a calculation module 1202 for further calculating Mmax、Mmin、Kb、KaN and M in formula of modulation degree of converter
Figure GDA0001345894000000221
And calculating to obtain a common-mode component change rate adjusting coefficient K.
In the embodiment of the invention, a preset modulation coefficient is needed, wherein the maximum modulation degree MmaxAnd minimum modulation degree MminIs the maximum modulation factor (generally M) allowed by the three-phase convertermaxNot more than 1.15) and minimum modulation (typically M)minLess than 1) is determined by the design and application scenario of the converter product, therefore, the maximum modulation degree MmaxAnd minimum modulation degree MminEquivalent to two fixed values; minimum rate of common mode change K between positive and negative clamp statesbThe method is determined by the scene where the three-phase converter is located, and can also be freely set by a user; maximum rate of common mode change and K between positive and negative clamp statesbDifference value K ofaIf the maximum rate of common mode variation between positive and negative clamping states allowed by the three-phase converter is 1, then KaIs equal to 1-Kb(ii) a The value of the modulation curvature parameter N is preset, the preset common-mode component adjusting formula is a linear formula when N is 1, and the preset common-mode component adjusting formula is a curve equation when N is larger than zero and is not equal to 1. Get M, M in get module 1201max、Mmin、Kb、KaAnd N, the value of the common-mode component change rate adjustment coefficient K can be calculated by the calculation module 1202 according to a formula, and Mmax、Mmin、Kb、KaAnd the value of N is preset and adjustable, then the value of K is determined by M, and the change is realizedThe modulation degree M of the current device flexibly adjusts the target of the change rate of the common-mode component.
Alternatively, in some embodiments of the present invention,
the obtaining module 1201 is further configured to obtain a preset maximum amplitude v of the modulation wavemaxAnd modulation degree minimum amplitude limit value vmin；
A calculation module 1202 further for calculating according to vmax、vminA common mode component change rate regulating coefficient K and a first phase initial modulation wave v in the three-phase initial modulation waveaV is calculated to obtainaCorresponding set of modulated waves { vmax-va，K*(vmax/2+vmin/2-va)，vmin-va}，vmax-vaIs v isaModulation wave variable v in corresponding positive clamping statemin-vaIs v isaCorresponding modulation wave variable, K (v) in negative-clamped statemax/2+vmin/2-va) Is v isaModulation wave variables in corresponding switching states;
a calculation module 1202 further for calculating according to vmax、vminA common-mode component change rate regulating coefficient K and a second-phase initial modulation wave v in the three-phase initial modulation wavebV is calculated to obtainbCorresponding set of modulated waves { vmax-vb，K*(vmax/2+vmin/2-vb)，vmin-vb}，vmax-vbIs v isbModulation wave variable v in corresponding positive clamping statemin-vbIs v isbCorresponding modulation wave variable, K (v) in negative-clamped statemax/2+vmin/2-vb) Is v isbModulation wave variables in corresponding switching states;
a calculation module 1202 further for calculating according to vmax、vminA common-mode component change rate regulating coefficient K and a second-phase initial modulation wave v in the three-phase initial modulation wavecV is calculated to obtaincCorresponding set of modulated waves { vmax-vc，K*(vmax/2+vmin/2-vc)，vmin-vc}，vmax-vcIs v iscModulation wave variable v in corresponding positive clamping statemin-vcIs v iscCorresponding modulation wave variable, K (v) in negative-clamped statemax/2+vmin/2-vc) Is v iscModulation wave variables in corresponding switching states;
a calculation module 1202 further for calculating according to va、vbAnd vcObtaining a modulated wave set { v } corresponding to the three-phase initial modulated wave by the corresponding modulated wave setmax-va，vmax-vb，vmax-vc，K*(vmax/2+vmin/2-va)，K*(vmax/2+vmin/2-vb)，K*(vmax/2+vmin/2-vc)，vmin-va，vmin-vb，vmin-vc}；
The calculating module 1202 is further configured to take an absolute value of each modulation wave variable in the common-mode modulation wave set, and select the modulation wave variable with the smallest absolute value as the common-mode modulation wave.
In the embodiment of the present invention, the maximum amplitude value and the minimum amplitude value of the modulation wave are preset, the obtaining module 1201 obtains the preset maximum amplitude value and the preset minimum amplitude value of the modulation wave, and since each switch in the three-phase current transformer corresponds to one switch and each switch has three clamping states, the calculating module 1202 has three clamping states according to vmax、vminA common mode component change rate regulating coefficient K and a first phase initial modulation wave v in the three-phase initial modulation waveaV is calculated to obtainaCorresponding set of modulated waves { vmax-va，K*(vmax/2+vmin/2-va)，vmin-va}，vmax-vaIs v isaModulation wave variable v in corresponding positive clamping statemin-vaIs v isaCorresponding modulation wave variable, K (v) in negative-clamped statemax/2+vmin/2-va) Is v isaThe modulation wave variables in the corresponding switching state are sequentially subjected to calculation to obtain second-phase initial modulationWave vbCorresponding set of modulated waves { vmax-vb，K*(vmax/2+vmin/2-vb)，vmin-vbAnd (6) calculating to obtain a third phase initial modulation wave vbCorresponding set of modulated waves { vmax-vb，K*(vmax/2+vmin/2-vb)，vmin-vbThe calculation module 1202 merges the modulation wave sets of the three-phase initial modulation waves into a modulation wave set { v } corresponding to the three-phase initial modulation wavesmax-va，vmax-vb，vmax-vc，K*(vmax/2+vmin/2-va)，K*(vmax/2+vmin/2-vb)，K*(vmax/2+vmin/2-vc)，vmin-va，vmin-vb，vmin-vcAnd taking an absolute value of each modulation wave variable in the common-mode modulation wave set, and selecting the modulation wave variable with the minimum absolute value as the common-mode modulation wave.
Alternatively, in some embodiments of the present invention,
the modulation module 1203 is specifically configured to perform waveform superposition on each phase of initial modulation waves in the three-phase initial modulation waves and the common mode modulation wave in a one-to-one correspondence manner, so as to obtain three-phase output modulation waves.
Alternatively, in some embodiments of the present invention,
an obtaining module 1201, configured to obtain a three-phase power grid voltage, a three-phase current, and a preset carrier amplitude;
the calculation module 1202 is further configured to perform phase locking processing on the three-phase power grid voltage to obtain a phase of a rotating coordinate system;
the calculating module 1202 is further configured to perform coordinate transformation on the three-phase current according to the phase of the rotating coordinate system to obtain a current of the rotating coordinate system;
the obtaining module 1201 is further configured to obtain a preset current reference value of the three-phase current coordinate transformation, and calculate a difference value between the preset current reference value and a current of the rotating coordinate system to obtain a current difference value;
the calculating module 1202 is further configured to process the current difference value through a proportional-integral PI regulator to obtain a rotation coordinate system regulation component;
the calculating module 1202 is further configured to perform inverse coordinate transformation on the adjustment component of the rotating coordinate system to obtain a three-phase initial modulation wave;
the calculating module 1202 is further configured to obtain a modulation wave amplitude of the three-phase initial modulation wave, and obtain a modulation degree of the converter according to a ratio of the modulation wave amplitude to a preset carrier amplitude.
In the embodiment of the invention, an obtaining module 1201 detects a three-phase converter to obtain three-phase power grid voltage, three-phase current and a preset carrier amplitude, a calculating module 1202 sends the three-phase power grid voltage to a phase-locked loop to obtain a phase of a rotating coordinate system, coordinate transformation is carried out on the three-phase current according to the phase of the rotating coordinate system to obtain current of the rotating coordinate system, a preset current reference value of the three-phase current coordinate transformation is obtained, a difference value between the preset current reference value and the current of the rotating coordinate system is calculated to obtain a current difference value, the current difference value is processed through a PI (proportional-integral) regulator to obtain a regulating component of the rotating coordinate system, anti-coordinate transformation is carried out on the regulating component of the rotating coordinate system to obtain a three-phase initial modulating wave, a modulating wave amplitude of the three-phase initial modulating wave.
The above embodiment describes the pulse width modulation method and the pulse width modulation system in detail, and the following describes an entity device of the pulse width modulation system, where the entity device is a controller shown in fig. 13, specifically as follows:
referring to fig. 13, the present invention provides a controller, including:
the processor 1301, the memory 1302 and the signal interface 1303 are connected to each other, the memory 1302 stores the operation instructions of the processor 1301,
a signal interface 1303 for obtaining three-phase initial modulation waves and a modulation degree of the converter;
the processor 1301 is configured to calculate a common mode component change rate adjustment coefficient according to preset modulation parameters and a converter modulation degree, where the preset modulation parameters include a preset maximum modulation degree, a preset minimum rate of common mode quantity change between positive and negative clamp states, a difference between the preset maximum rate and the preset minimum rate of common mode quantity change between the positive and negative clamp states, and a modulation curvature parameter;
the processor 1301 is further configured to calculate a modulation wave set corresponding to the three-phase initial modulation wave according to a preset modulation wave maximum amplitude, a preset modulation wave minimum amplitude, a preset three-phase initial modulation wave and a preset common-mode component change rate adjustment coefficient, and select a modulation wave with a minimum absolute value from the modulation wave set as a common-mode modulation wave;
the processor 1301 is further configured to perform waveform superposition on the three-phase initial modulation wave and the common-mode modulation wave to obtain a three-phase output modulation wave.
In the embodiment of the invention, the common mode component change rate adjustment coefficient is calculated by a processor 1301 according to preset modulation parameters and a converter modulation degree acquired by a signal interface 1303, wherein the preset modulation parameters include a preset maximum modulation degree, a preset minimum common mode change rate between a positive clamping state and a negative clamping state, a difference value between the preset maximum common mode change rate and the minimum common mode change rate between the positive clamping state and the negative clamping state, and modulation curvature parameters, the processor 1301 calculates a modulation wave set corresponding to a three-phase initial modulation wave according to a preset modulation wave maximum amplitude limit value, a modulation wave minimum amplitude limit value, a three-phase initial modulation wave and the common mode component change rate adjustment coefficient, selects a modulation wave with the minimum absolute value from the modulation wave set as a common mode modulation wave, and finally performs waveform superposition on the three-phase initial modulation wave and the common mode modulation wave, compared with the method I in the prior art, the change rate of the common-mode component is determined by the modulation degree of the converter, changes along with the change of the modulation degree of the converter, and has no amplitude limiting link, so that the influence caused by improper amplitude limiting value can be avoided, the stability and harmonic characteristic of the three-phase converter are improved, and compared with the method II in the prior art, the change rate of the common-mode component is determined by the modulation degree of the converter, and self-adaptive adjustment is realized.
The controller shown in FIG. 13 also includes one or more storage media 1304 (e.g., one or more mass storage devices) that stores applications 1305 or data 1306. Memory 1302 and storage media 1304 may be, among other things, transient storage or persistent storage. The program stored in the storage medium 1304 may include one or more modules (not shown), each of which may include a sequence of instructions operating on a server. Further, the processor 1301 may be arranged in communication with the storage medium 1304 to execute a series of instruction operations in the storage medium 1304 on a server.
The controller may also include one or more operating systems 1307, such as Windows Server, MacOS XTM, UnixTM, LinuxTM, or FreeBSDTM, among others.
It should be noted that the pv inverter application system shown in fig. 7 in the present invention may be equivalent to the two-level rectifier and inverter structure shown in fig. 14, in addition, it may also be a three-level rectifier and converter structure shown in fig. 15, a five-level rectifier and converter structure shown in fig. 16, or a cascaded multi-level rectifier and converter structure shown in fig. 17.
It should be understood that, in various embodiments of the present invention, the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims (11)

1. A pulse width modulation method is applied to a three-phase current transformer, and is characterized by comprising the following steps:
acquiring three-phase initial modulation waves and a modulation degree of a converter;
calculating to obtain a common-mode component change rate adjusting coefficient according to preset modulation parameters and the modulation degree of the converter, wherein the preset modulation parameters comprise a preset maximum modulation degree, a preset minimum rate of common-mode quantity change between positive and negative clamping states, a preset difference value between the maximum rate and the minimum rate of common-mode quantity change between the positive and negative clamping states and a modulation curvature parameter of the three-phase converter;
calculating to obtain a modulation wave set corresponding to the three-phase initial modulation wave according to a preset maximum amplitude limit value of the modulation wave, a preset minimum amplitude limit value of the modulation wave, the three-phase initial modulation wave and the common-mode component change rate adjustment coefficient, and selecting the modulation wave with the minimum absolute value from the modulation wave set as a common-mode modulation wave;
and performing waveform superposition on the three-phase initial modulation wave and the common-mode modulation wave to obtain a three-phase output modulation wave.
2. The pulse width modulation method according to claim 1, wherein the calculating a common mode component change rate adjustment coefficient according to a preset modulation parameter and the converter modulation degree comprises:
obtaining the preset maximum modulation degree M of the three-phase convertermaxPresetting minimum modulation MminPresetting minimum speed K of common mode quantity change between positive and negative clamping statesbPresetting the difference K between the maximum rate and the minimum rate of the common mode quantity change between the positive clamping state and the negative clamping stateaAnd modulating the curvature parameter N, N is greater than 0;
the M is addedmax、Mmin、Kb、KaN and the modulation factor M of the converter into the formula
Figure FDA0002259434980000011
And calculating to obtain a common-mode component change rate adjusting coefficient K.
3. The pulse width modulation method according to claim 2, wherein the calculating, according to a preset maximum amplitude limit value of a modulation wave, a minimum amplitude limit value of a modulation wave, the three-phase initial modulation wave and the common-mode component change rate adjustment coefficient, to obtain a set of modulation waves corresponding to the three-phase initial modulation wave, and selecting a modulation wave with a smallest absolute value from the set of modulation waves as a common-mode modulation wave, includes:
obtaining the maximum limit amplitude v of the preset modulation wavemaxAnd modulation degree minimum amplitude limit value vmin；
According to said vmaxSaid vminThe common-mode component change rate regulating coefficient K and a first-phase initial modulation wave v in the three-phase initial modulation waveaCalculating to obtain the vaCorresponding set of modulated waves { vmax-va，K*(vmax/2+vmin/2-va)，vmin-vaV, said vmax-vaIs the vaModulated wave variable in corresponding positive clamp state, said vmin-vaIs the vaModulation wave variable in corresponding negative-clamped state, said K (v)max/2+vmin/2-va) Is the vaModulation wave variables in corresponding switching states;
according to said vmaxSaid vminThe common-mode component change rate regulating coefficient K and a second-phase initial modulation wave v in the three-phase initial modulation wavebCalculating to obtain the vbCorresponding set of modulated waves { vmax-vb，K*(vmax/2+vmin/2-vb)，vmin-vbV, said vmax-vbIs the vbModulated wave variable in corresponding positive clamp state, said vmin-vbIs the vbModulation wave variable in corresponding negative-clamped state, said K (v)max/2+vmin/2-vb) Is the vbModulation wave variables in corresponding switching states;
according to said vmaxSaid vminThe common-mode component change rate regulating coefficient K and a second-phase initial modulation wave v in the three-phase initial modulation wavecMeter for measuringCalculating the vcCorresponding set of modulated waves { vmax-vc，K*(vmax/2+vmin/2-vc)，vmin-vcV, said vmax-vcIs the vcModulated wave variable in corresponding positive clamp state, said vmin-vcIs the vcModulation wave variable in corresponding negative-clamped state, said K (v)max/2+vmin/2-vc) Is the vcModulation wave variables in corresponding switching states;
according to said vaSaid vbAnd said vcObtaining a set of modulation waves { v ] corresponding to the three-phase initial modulation wavemax-va，vmax-vb，vmax-vc，K*(vmax/2+vmin/2-va)，K*(vmax/2+vmin/2-vb)，K*(vmax/2+vmin/2-vc)，vmin-va，vmin-vb，vmin-vc}；
And taking an absolute value of each modulation wave variable in the common-mode modulation wave set, and selecting the modulation wave variable with the minimum absolute value as the common-mode modulation wave.
4. The pulse width modulation method according to any one of claims 1 to 3, wherein the waveform-superimposing the three-phase initial modulation wave and the common mode modulation wave to obtain a three-phase output modulation wave includes:
and carrying out waveform superposition on each phase of initial modulation wave in the three-phase initial modulation wave and the common mode modulation wave in a one-to-one correspondence manner to obtain a three-phase output modulation wave.
5. The pulse width modulation method according to claim 4, wherein the obtaining of the three-phase initial modulation waveform and the converter modulation degree comprises:
acquiring three-phase power grid voltage, three-phase current and a preset carrier amplitude;
performing phase locking processing on the three-phase power grid voltage to obtain a phase of a rotating coordinate system;
according to the phase of the rotating coordinate system, coordinate transformation is carried out on the three-phase current to obtain a current of the rotating coordinate system;
acquiring a preset current reference value of the three-phase current coordinate transformation, and calculating a difference value between the preset current reference value and the current of the rotating coordinate system to obtain a current difference value;
processing the current difference value through a proportional integral PI regulator to obtain a rotating coordinate system regulation component;
carrying out inverse coordinate transformation on the adjustment component of the rotating coordinate system to obtain a three-phase initial modulation wave;
and obtaining the modulation wave amplitude of the three-phase initial modulation wave, and obtaining the modulation degree of the converter according to the ratio of the modulation wave amplitude to the preset carrier amplitude.
6. A pulse width modulation system for use with a three-phase current transformer, said system comprising:
the acquisition module is used for acquiring three-phase initial modulation waves and the modulation degree of the converter;
the calculation module is used for calculating a common-mode component change rate adjustment coefficient according to preset modulation parameters and the modulation degree of the converter, wherein the preset modulation parameters comprise a preset maximum modulation degree, a preset minimum common-mode quantity change rate between positive and negative clamping states, a difference value between the preset maximum common-mode quantity change rate and the preset minimum common-mode quantity change rate between the positive and negative clamping states and modulation curvature parameters of the three-phase converter;
the calculation module is further used for calculating a modulation wave set corresponding to the three-phase initial modulation wave according to a preset maximum amplitude limit value of the modulation wave, a preset minimum amplitude limit value of the modulation wave, the three-phase initial modulation wave and the common-mode component change rate adjustment coefficient, and selecting the modulation wave with the minimum absolute value from the modulation wave set as the common-mode modulation wave;
and the modulation module is also used for performing waveform superposition on the three-phase initial modulation wave and the common-mode modulation wave to obtain a three-phase output modulation wave.
7. The pulse width modulation system of claim 6,
the obtaining module is further configured to obtain a preset maximum modulation degree M of the three-phase convertermaxPresetting minimum modulation MminPresetting minimum speed K of common mode quantity change between positive and negative clamping statesbPresetting the difference K between the maximum rate and the minimum rate of the common mode quantity change between the positive clamping state and the negative clamping stateaAnd modulating the curvature parameter N, N is greater than 0;
the computing module is further configured to compare the Mmax、Mmin、Kb、KaN and the modulation factor M of the converter into the formulaAnd calculating to obtain a common-mode component change rate adjusting coefficient K.
8. The pulse width modulation system of claim 7,
the obtaining module is further configured to obtain a preset maximum amplitude v of the modulation wavemaxAnd modulation degree minimum amplitude limit value vmin；
The computing module is further configured to compute v from the datamaxSaid vminThe common-mode component change rate regulating coefficient K and a first-phase initial modulation wave v in the three-phase initial modulation waveaCalculating to obtain the vaCorresponding set of modulated waves { vmax-va，K*(vmax/2+vmin/2-va)，vmin-vaV, said vmax-vaIs the vaModulated wave variable in corresponding positive clamp state, said vmin-vaIs the vaModulation wave variable in corresponding negative-clamped state, said K (v)max/2+vmin/2-va) Is the vaCorresponding switching stateA system wave variable;
the computing module is further configured to compute v from the datamaxSaid vminThe common-mode component change rate regulating coefficient K and a second-phase initial modulation wave v in the three-phase initial modulation wavebCalculating to obtain the vbCorresponding set of modulated waves { vmax-vb，K*(vmax/2+vmin/2-vb)，vmin-vbV, said vmax-vbIs the vbModulated wave variable in corresponding positive clamp state, said vmin-vbIs the vbModulation wave variable in corresponding negative-clamped state, said K (v)max/2+vmin/2-vb) Is the vbModulation wave variables in corresponding switching states;
the computing module is further configured to compute v from the datamaxSaid vminThe common-mode component change rate regulating coefficient K and a second-phase initial modulation wave v in the three-phase initial modulation wavecCalculating to obtain the vcCorresponding set of modulated waves { vmax-vc，K*(vmax/2+vmin/2-vc)，vmin-vcV, said vmax-vcIs the vcModulated wave variable in corresponding positive clamp state, said vmin-vcIs the vcModulation wave variable in corresponding negative-clamped state, said K (v)max/2+vmin/2-vc) Is the vcModulation wave variables in corresponding switching states;
the computing module is further configured to compute v from the dataaSaid vbAnd said vcObtaining a set of modulation waves { v ] corresponding to the three-phase initial modulation wavemax-va，vmax-vb，vmax-vc，K*(vmax/2+vmin/2-va)，K*(vmax/2+vmin/2-vb)，K*(vmax/2+vmin/2-vc)，vmin-va，vmin-vb，vmin-vc}；
The calculation module is further configured to take an absolute value of each modulation wave variable in the common-mode modulation wave set, and select a modulation wave variable with a smallest absolute value as the common-mode modulation wave.
9. The pulse width modulation system according to any one of claims 6 to 8,
the modulation module is specifically configured to perform waveform superposition on each phase of the initial modulation wave in the three-phase initial modulation wave and the common mode modulation wave in a one-to-one correspondence manner, so as to obtain a three-phase output modulation wave.
10. The pulse width modulation system of claim 9,
the acquisition module is used for acquiring three-phase power grid voltage, three-phase current and a preset carrier amplitude;
the calculation module is also used for carrying out phase locking processing on the three-phase power grid voltage to obtain a phase of a rotating coordinate system;
the calculation module is further used for performing coordinate transformation on the three-phase current according to the phase of the rotating coordinate system to obtain a current of the rotating coordinate system;
the acquisition module is further used for acquiring a preset current reference value of the three-phase current coordinate transformation, and calculating a difference value between the preset current reference value and the current of the rotating coordinate system to obtain a current difference value;
the calculation module is also used for processing the current difference value through a proportional integral PI regulator to obtain a rotating coordinate system regulation component;
the calculation module is further configured to perform inverse coordinate transformation on the rotating coordinate system adjustment component to obtain a three-phase initial modulation wave;
the calculation module is further configured to obtain a modulation wave amplitude of the three-phase initial modulation wave, and obtain a modulation degree of the converter according to a ratio of the modulation wave amplitude to the preset carrier amplitude.
11. A controller applied to a three-phase converter is characterized by comprising:
the processor, the memory and the signal interface are connected with each other, the memory is stored with the operation instruction of the processor,
the signal interface is used for acquiring three-phase initial modulation waves and the modulation degree of the converter;
the processor is used for calculating to obtain a common mode component change rate adjusting coefficient according to preset modulation parameters and the modulation degree of the converter, wherein the preset modulation parameters comprise a preset maximum modulation degree, a preset minimum rate of common mode quantity change between positive and negative clamping states, a difference value between the preset maximum rate and the preset minimum rate of common mode quantity change between the positive and negative clamping states and modulation curvature parameters of the three-phase converter;
the processor is further configured to calculate a modulation wave set corresponding to the three-phase initial modulation wave according to a preset maximum amplitude limit of the modulation wave, a preset minimum amplitude limit of the modulation wave, the three-phase initial modulation wave and the common-mode component change rate adjustment coefficient, and select the modulation wave with the smallest absolute value from the modulation wave set as the common-mode modulation wave;
the processor is further configured to perform waveform superposition on the three-phase initial modulation wave and the common-mode modulation wave to obtain a three-phase output modulation wave.
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Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110071680B (en) * 2019-05-14 2021-05-14 深圳市正弦电气股份有限公司 PWM modulation method and system for reducing temperature rise of frequency converter
CN112803823B (en) * 2019-11-13 2022-09-23 华为技术有限公司 Pulse width modulation method, inverter and controller
CN111371301B (en) * 2020-03-13 2021-11-02 中南大学 IGBT junction temperature control method and system for two-level traction inverter
GB2602338B (en) * 2020-12-23 2023-03-15 Yasa Ltd A Method and Apparatus for Cooling One or More Power Devices
GB2605557B (en) 2020-12-23 2023-05-24 Yasa Ltd A method and apparatus for generating a three-phase voltage
CN112821790B (en) * 2021-01-04 2022-08-12 台达电子企业管理（上海）有限公司 Three-phase converter and control method thereof
WO2022188950A1 (en) * 2021-03-09 2022-09-15 Huawei Digital Power Technologies Co., Ltd. Double-reference pulse-width modulation for torque minimization of ac machines
CN113098308B (en) * 2021-03-11 2022-07-12 中国长江三峡集团有限公司 Neutral point potential balancing method of three-level converter on direct current side suitable for any bridge arm number
CN114583989B (en) * 2021-03-22 2023-09-22 上海正泰电源系统有限公司 Three-level inverter modulation mode switching method, device, equipment and storage medium
EP4120528A1 (en) * 2021-07-16 2023-01-18 Siemens Aktiengesellschaft Power converter
CN113556053B (en) * 2021-07-21 2022-10-28 华为数字能源技术有限公司 Control method of three-phase multi-level inverter and inverter system
CN113691157B (en) * 2021-08-30 2022-04-19 燕山大学 Rotation discontinuous control method for modular multilevel converter
CN114977870B (en) * 2022-06-16 2022-12-27 安徽理工大学 Unified algorithm for realizing T-type three-level discontinuous modulation carrier
CN115913002B (en) * 2022-11-25 2023-10-13 江苏国科智能电气有限公司 Three-level inverter of brushless direct current motor and control method thereof
CN116865584B (en) * 2023-09-04 2023-11-21 西安千帆翼数字能源技术有限公司 Two-level converter, control method, SPWM (sinusoidal pulse Width modulation) method and SPWM (sinusoidal pulse Width modulation) system

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5852558A (en) * 1997-06-20 1998-12-22 Wisconsin Alumni Research Foundation Method and apparatus for reducing common mode voltage in multi-phase power converters
US6023417A (en) * 1998-02-20 2000-02-08 Allen-Bradley Company, Llc Generalized discontinuous pulse width modulator
US7400518B2 (en) * 2006-05-22 2008-07-15 Rockwell Automation Technologies, Inc. Modulation methods and apparatus for reducing common mode noise
JP5161180B2 (en) * 2009-09-17 2013-03-13 日立アプライアンス株式会社 Motor drive device, inverter device, converter device, and refrigeration air conditioner
JP5830298B2 (en) * 2011-08-04 2015-12-09 株式会社ダイヘン Grid-connected inverter device
CN103051227B (en) * 2012-12-21 2015-04-29 燕山大学 Modulation method of three-phase Z-source neutral point clamped multi-level photovoltaic inverter
CN105207511B (en) * 2014-06-30 2018-09-21 华为技术有限公司 A kind of control method of converter, device and system
JP6176495B2 (en) * 2014-08-19 2017-08-09 富士電機株式会社 3-level inverter control method and control apparatus
CN104753375B (en) * 2015-04-10 2017-12-05 上海兆能电力电子技术有限公司 A kind of three-level inverter DPWM control methods
CN104883087B (en) * 2015-05-04 2017-09-22 长安大学 A kind of multi-electrical level inverter universal pulse width modulating method
CN105245123B (en) * 2015-10-16 2017-10-20 燕山大学 Three-phase neutral-point-clamped three-level inverter one-dimensional modulation common mode current suppressing method
CN106100430B (en) * 2016-08-23 2018-07-06 合肥工业大学 The carrier wave implementation method of the low common-mode voltage modulation of three-phase five-level inverter

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